Starting means for electric motors



July is 1924.

1,501,410 1.. w. LUND STARTING MEANS FOR ELECTRIC MOTORS Filed Sept. 14. 1922 2 Sheets-Sheet l INVENTOR.

A T T ORNE Y.

July 15, 1924. 1,501,410

L. w. LUND STARTING MEANS FOR ELECTRIC MOTORS Fil t. 14, 1922 2 1101114111191 2 4 IN VEN TOR.

ATTORNEY.

Patented July 15, 1924.

UNIT D STATES PATENT caries.

in: w. LUND, or DULUTH, mason. V suarnro nuns ron mncmc aromas- Applicatio ma September 14, 102:. mm Io. seam.

To all whom it may concern:

Be it known that I, LEE W. LUND, a citizen of the United States, residing at Duluth, in the county of St. Louis and State of Minnesota, have invented useful Improvements in Startin Means for Electric Motors,-of which the ollowin'g is a specification, reference being had therein to the accompanying drawing.

This invention relates to starting means for induction electric motors and has special reference to automatic control of said start ing means. v

g The principal object of the invention is to provide simple and effective means whereby to automatically render the starting circuit inactive when'the motor attains a predetermined speed. I

Other ob'ects and advantages will appear in the'furt er description of the invention.

Referring to the accompanying drawing forming part of-this application in which and Figure '1 is an elevation of the interthe wiring diagram:

Figure 2 is a broken side elevation of the assembled motor showing the switch in elevation and portions of the interior of the motor in section: a

Figure 3 is a top plan view of the circuit making and breaking mechanism or switch: an

Figure 4 is a front elevation. of the switch illustrating the wiring diagram. 41 represents the casing of the motor; 2 the rotor of the motor; 3 the stator of the motor, and 4 the rotor or armature shaft.

To the inner face of the end 5 of the motor casing is securely attached a sleeve 6 it being concentric with the shaft 4 and about same, having formed integrally therewith an annular flange? through which the fastening is made to the endof the casing in any desired manner.

A Secondsleeve 8 is reciprocably mounted upon the sleeve 6 and carries rigidly fixed to its outer end a spider shaped disc or armature 9, the extreme radially extending portions or armsof which are bent slightly towards the face of the rotor 2 of the motor but do notcontact therewith, said armature being of a diameter slightly ter than the rotor of the motor, so as to most readily certain new and 8 is fully retracted. like reference characters indicate like parts:

tor by the effected by magnetic leakage of the motor during the initial starting of same.

The sleeve 8 is normally held in retracted position upon the sleeve 6 by means of the helical spring 10 within the latter sleeve, as the sleeve 8 carries two opposed radially disposed screws 11 protruding inwardly through the slotted openings 12 within the sleeve 6. The screws 11 are sufficiently long -to be engaged by the innermost end of ,the

spring 10, the opposite end of said spring impinging against the inwardly lugs 21. of the outermost end of the sleeve 6.

Supported upon the upper portion of the annular holding flan e 7 is a rectangularly shaped terminal bloc 13 carrying the two opposed U-shaped contact members 14 and 15, the free ends of which are turned towards each other and offset slightly as at 16, they being so shaped as to remain spaced apart normally when the reciprocal sleeve The electric circuit connections to the automatic switch are indicated at 18 and 17 the former leading to the starting winding of the motor and ultimately to the automatic switch, and the latter to the other pole of the automatic switch; while the main winding of the motor is indicated at 19.

A fiber or other insulated block 20 is fastened in. upright position on one edge to the upper side of the sleeve 8 and this block is provided with a notch adjacent one end into which the free end of the terminal 14 is mounted so that as the sleeve 8 with with its armature 9 isdrawn outwardly the free end of the terminal 14wi1l contact the end-of the terminal 15, as at 16, thus closing the starting circuit. Upon the applicatlon of current to the motor, the armature 9 is drawn magnetically towards the primary and secondary members of the niomagnetic leakage which is set up through the combined magnetic flux of said primary and secondary members which are opposed to each other during the initial starting and previous to the rotor attaining its runnin speed as well known to those versed in t e art. 7

As soon as the current flows in the starting coils, the rotor begins revolve, and as the speed of the same increases the magnetic leakage decreases until it becomes ineffective in retaining the armature of the projecting one pole of switch .when the expensive action of the helical spring 10 will restore same to normaicy, ami separate the contacts 14; alfi 15 as is, ObWOHS, thns breaking the starting circuit when the motor will continue in operation.

7 thereupon,

- for comprising Having I claimant desire to secure ent is:

1. The combination with an induction motor having a main motor winding and an auxiliary starting winciing, of an automaticelly controlleii starting switch therethns describei my invention, what by Letters Patsieeves concentric with motor, the outermost being reciprocable 2.116. carrying an armature two normally space contact within said switch, an expansive the telescopic sleeves in with the contact points spring for holding their retracted position two telescopically monnte& the ermatnre of the one of semi sleeves points thus spaced apart, and means wherc- M In testiinony whereof I herennto efix my cooperatively associate making Y Witnesses:

S. C. Bnonson, S. Gno. STEVEN;

are engaged by the d 30 and breaksaid armature being 

